Wedgemaker

ABSTRACT

An improved method and apparatus for making insulating wedges for use in an automatic coil placing machine which first severs the wedge material and then contemporaneously forms and slits the wedge is disclosed. The machine is adapted to provide wedges of at least two different lengths and to slit only the longer wedges. The improvement comprises a power operated punch, a forming die, and a plurality of cutting surfaces some of which are retractable wherein the punch forces the wedge blanks through the forming die and past the cutting surfaces in a single stroke.

United States Patent Walker et al.

[451 Oct. 3, 1972 [54] WEDGEMAKER [72] Inventors: Robert G. Walker,Brighton, Mich.;

Donald E. Hill, Ft. Wayne, Ind

[73] Assignee: Industra Products Inc., Fort Wayne,

Ind.

[22] Filed: Oct. 30, 1970 [21] Appl. No.: 85,355

[52] US. Cl. ..29/205 E, 29/596 [51] Int. Cl. ..H02k 15/00 [5 8] Fieldof Search ..29/205 E, 203 D, 205 D, 596

[56] v References Cited UNITED STATES PATENTS 3,519,862 7/1970 Walker..3l0/2l4 Primary Examiner-Thomas H. Eager Att0rney-Jeffers and Rickert[5 7] ABSTRACT 9 Claims, 5 Drawing Figures Pmmmm m2 3,694.88! SHEET 2 0F2 INVENTORS DONALD E. HILL ROBERT G. WALKER ATTORNEYS WEDGEMAKER CROSSREFERENCE TO RELATED APPLICATIONS ing the Same. The present invention isintimately related to and used in conjunction with the copendingapplication entitled Feed Mechanism Overload Release filed Aug. 6, 1970,Ser. No. 61,681 in the name of Robert G. Walker.

BACKGROUND OF THE INVENTION The present invention is concerned verybroadly with the automatic manufacture of dynamoelectric machinery andmore especially with the forming and inserting of prewound coils andstrips of insulating material in the magnetic members of such machines.Specifically, the present invention is concerned with the portion of amachine for such automatic fabrication which makes the insulating wedgesfor the stator.

One type of insulating wedge which may be manufactured according to theteachings of the present invention is illustrated in FIG. 2 of theaforementioned U.S. Pat. No. 3,519,862 U.S. Pat. No. and FIGS. 4, 5a and5b of that application illustrate one machine capable of manufacturingsuch wedges. The actual production techniques relied upon prior to thepresent invention for manufacturing this type of wedge consisted of areel which contained a long strip of the insulating material such asmylar being fed first to a V-shape slitting die which when actuated slitthe front end of one insulating wedge and the back end of the precedingwedge all prior to the time that the wedge strip was severed intoindividual wedges. This V-shape die was a good distance removed from thesevering die which resulted in substantial problems of synchronizing thesevering die so that it parted the mylar at the appropriate point. Theprior art process also required rather sophisticated programming when itwas desired to supply some wedges having slits and some (generallyshorter) wedges without these slits. The prior art V-shape slitting diewas actually mounted prior to the wedge maker feeding mechanism and anyslippage in the feeding mechanism of course resulted in defectivewedges.

SUMMARY OF THE INVENTION It is a primary object of the present inventionto provide an improved wedge maker.

The primary object of the present invention is achieved by providing thestructure which slits the wedges in a position subsequent to theinsulating material feed mechanism. By providing this notching mechanismsubsequent to the feed mechanism any slippage in the feed mechanismresults in only one defective wedge rather than a series of defectivewedges. This change in the sequence of operations also results in amaterially simplified routine when it is desired to provide both slitand unslit wedges.

Accordingly, it is another object of the present invention to provide awedge making machine which can automatically produce both slit andunslit wedges and/or wedges of varying lengths in one processingsequence.

According to the teachings of the present invention the wedge is formedand slit in one operation. This is achieved by providing a poweroperated punch, a forming die, and a plurality of cutting surfaceswherein the punch forces the wedge blanks through the forming die andpast the cutting surfaces in a single stroke.

It is therefore a further object of the present invention to provide asimplified wedge maker.

It is yet another object of the present invention to provide a wedgemaker of less initial cost and diminished maintenance expense.

These and other objects and advantages of the present invention willappear more clearly from the following detailed disclosure read inconjunction with the accompanying drawing in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a slitphase insulation wedge;

FIG. 2 is a perspective view of a bore slot wedge;

FIG. 3 is a plan view of a portion of a motor stator illustrating therelative placement of the several insulating wedges;

FIG. 4 is a side view of the wedge maker of the present inventionshowing the insulation feed mechanism; and

FIG. 5 is a portion of the cross sectional view along the line 5-5 ofFIG. 4 showing the punch, forming die and cutting surfaces of the wedgemaker.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 illustrateinsulating wedges manufactured according to the teachings of the presentinvention and FIG. 3 illustrates a partial cross sectional view of anelectric motor stator illustrating how those wedges might be positionedwithin that stator. The wedge 11 of FIG. 1 is a relatively long phaseinsulation wedge and might for example be used to separate the mainwinding 13 from the phase winding 15 of FIG. 3. This wedge is cut from aflat strip of mylar" or other insulating material and provided with twopairs of slits 17a, 17b and 18a, 18b the slits of each of said pairsextending inwardly from opposite edges of the strip toward each other.The entire wedge is bent in a U- shape along its length and when inposition in a stator the tabs formed at the ends of the wedge due to theresilient nature of the insulating material tend to depart from theU-shape given them during the forming process and return somewhat totheir original flat position thus preventing the wedge from slidingaxially in the stator slot. This would be extremely important if forexample the main winding 13 were first inserted in the stator, then thephase insulating wedge 11 was inserted and then the phase winding 15 wasinserted in the stator. This last step of insertion often causes priorart wedges to be moved axially within the stator sufficiently far thatthey no longer perform their intended insulating function. The tabsformed by the slitting process are not necessary on the shorter boreslot insulating wedge 19 illustrated in FIG. 2 since-the insertion ofthis wedge is usually the last step in the fabrication process. Itshould be noted that the bore wedge 19 is of approximately the samelength as the stator being assembled while the phase insulation wedge 11is sufficiently longer than the stator to allow the end tabs to extendbeyond the ends of the stator and perform their intended holdingfunction.

The stator when presented to the machine of the present invention mayalready have cuffed stator slot wedges 21 in place in the stator slotsor these slots may have an insulating coating such as an epoxy resinapplied to them. A coil placing machine would then normally insert thewinding 13 along with the phase insulation wedge 11 and then the statorwould be removed from the coil placing machine and placed on a so-calleddrift press which serves to push the winding 13 along with the phaseinsulation wedge 11 outward radially in the stator to make room for theinsertion of additional coils. This drifting process also has a tendencyto shift the wedge 11 axially but again this is prevented by the tabs atthe ends of the wedge which were formed by the slitting process. Thestator would then be returned to the coil placing machine for theinsertion of the coil winding 15 and the bore slot wedge 19. If morethan two windings were desired, this process might be repeated severaltimes with each of the intermediate phase insulation wedges beingconfigured as shown in FIG. 1 and with the last bore slot wedge havingthe configuration of FIG. 2. Thus, cuffed stator slot wedges if presentare slightly longer than the axial length of the stator to allow thecuff portion to extend outside and prevent the inadvertent dislodgementof this wedge, the phase insulation wedges 1 1 are sufficiently longerthan the cuffed stator slot wedges to allow the tabs formed by theslitting process to extend outwardly and over the cuff at either end ofthe stator and the bore slot wedges 19 are approximately the same lengthas the stator though they might be slightly longer in certainapplicatrons.

From the discussion so far, it can be seen that the coil placing machinewhich inserts the coil 13 in the stator also forms and inserts the phaseinsulation wedge 11 in a single pass through the stator. This samemachine can of course be used to insert the coil 15 and its associatedinsulating wedge however, since this last wedge is a shorter unslitwedge, the portion of the coil placing machine which fabricates thesewedges must be modified between the pass which inserts the coil 13 andthe pass which inserts the coil 15. This modification is the very heartof the present invention.

Turning now to FIG. 4 a primary source of power drives the gear 23 whichis provided with an off center pin not shown which slides in a slot inthe lever arm 25. This lever arm 25 pivots at the point 27 and transmitsmotion along the connecting link 29 to a second lever arm 31. Theconnecting link 29 forms the subject matter of the earlier mentionedFeed Mechanism Overload Release application Ser. No. 61,681. The secondlever arm 31 is pivoted at point 33 and thus by way of a secondconnecting link 35 imparts a back and forth linear motion to the slidingblock 37. This block 37 carries a pawl like member 39 which alternatelygrips and releases the insulating material between the pawl 39 andmaterial support 40 so as to feed the material in increments of a lengthdetermined by the control signals imparted to the hydraulic cylinder 41.This cylinder 41 is actuated by accurately metered quantities ofhydraulic fluid or air supplied by way of tube 43 which serve to extendor retract the rod 45 and thus vary the distance between the connectinglink pivot point 47 and the lever arm pivot point 27. Varying thedistance between these two points of course varies the extreme travelfor the sliding block 37 and thus varies the length of insulatingmaterial fed per cycle.

The insulating material is fed from a roll of stock material or othersource and passes under an idler roller 46 and into the feed mechanism.The feed mechanism may have a second spring loaded feed pawl 42 toprevent the retracting of the material. The insulating material is fedthrough the feed mechanism along a passage way 49 and past the cutter51. The cutter 51 is actuated once for each revolution of the gearedwheel 23 and thus each time the feed mechanism goes through one cyclethe cutter cuts off a wedge blank having a length equal to the extremetravel of the sliding block 37. As will be noted subsequently thiscutting operation sometimes causes the severed wedge blank to movevarying distances in its passageway and since its positioning subsequentto the cutting operation is critical some means must be provided forholding the wedge blank in a definite position as the cutting operationoccurs. The evolution of the insulating material after being severedinto wedge blanks of prescribed lengths is best seen in reference toFIG. 5.

At the time the insulating material is severed into a wedge blank, it isin the position illustrated by dotted lines at 53 of FIG. 5. The punch55 is retracted from and above the unforrned wedge blank 53 at this timebut soon thereafter begins its downward travel and its motion inconjunction with the edges of the forming die 57 fold this previouslyflat wedge blank into a U-shape. Directly below the forming die 57 islocated a plurality of cutting surfaces 59 which in conjunction with thedownward motion of the punch 55 cut the insulating material to providethe slits 17 and 18 of FIG. 1. After slitting, the punch continues itsdownward motion and deposits the formed and slit insulating wedge in anotch 61 on a cylinder. At this point, the punch 55 retracts to aposition above 53 to allow a new wedge blank to be inserted and formed,the cylinder is indexed by link of FIG. 4, new material is fed and thepunch forms, slits and deposits another wedge in a new slot. The axiallength of the cylinder exceeds the length of the longest of theinsulating wedges to be fabricated and accordingly the sides of thenotches 61 hold both the main portions of the wedge and the tabs formedby the slitting operation at the same position for insertion in thestator. When the cylinder has the appropriate notches filled withwedges, all wedges are axially pushed from the cylinder into a statoralong with a coil being inserted by the coil placing machine.

As noted earlier, the operation of severing the insulating material intowedge blanks of the desired length of the cutter 51 would often causethe severed wedge blank to jump forward by varying amounts. To overcomethis problem, the punch 55 is provided with a piano wire spring 63 whichrides the surface of the insulating material when it is in its position53 and the punch is in its completely retracted location. The additionalfriction caused on the wedge blank by this spring either eliminates thejumping or at least limits these jumps to controlled and consistentamounts so that the slits 1'7 and 18 are properly located relative tothe wedge blank.

There are of course, a pair of cutting surfaces 59 to cut for examplethe pair of slits 17a and 17b of FIG. 1 and a second pair of cuttingsurfaces either directly behind or directly in front of this pair ofcutting surfaces 59 to provide the slits 18a and 18b in the wedge ofFIG. 1. One such pair of cutting surfaces is provided with connectinglinks 65 which when actuated by an air or hydraulic cylinder 67 of FIG.4 serve to pull the cutting surfaces away from the wedge being formed sothat that wedge is not slit by the cutting surfaces 59. As was notedearlier, it is desirable in the fabrication of stators to provide a longslit wedge as illustrated in FIG. 1 and a shorter unslit wedge asillustrated in FIG. 2. The present invention thus need only retract theone pair of cutting edges since the shorter wedge does not extendsufiiciently far beyond the cutter 51 to be slit during its formingprocess by the unretracted pair of cutter blades. It is of course withinthe scope of the present invention to also retract the second pair ofcutting edges if longer unslit wedges were desired. The punch formingdie and cutters illustrated in FIG. 5 form and slit the wedge in asingle cycle of the punch and while the forming and cutting is notsimultaneous it would be made so by fashioning the forming dies 57 withnarrow slits which would accept the cutting surfaces 59. When thisforming and cutting or slitting occurs either simultaneously orsequentially during one cycle of the punch 55, the forming and slittingare said to be performed contemporaneously.

The present invention then provides for a means for feeding the wedgematerial in increments of first, second and perhaps third and fourthlengths depending upon the position of the air cylinder 41 which in turndefines the lever arm length of the feeding mechanism. The wedgematerial is severed into wedge blanks of a length determined by that aircylinder position by the cutters 51a and 51b and these wedge blanks arethen contemporaneously formed and slit by the operation of the poweroperated punch 55, the forming die 57 and the plurality of cuttingsurfaces 59. The pairs of cutting surfaces are so positioned that whenthe air cylinder is retracted and shorter wedges are being fed and cut,the shorter wedges do not extend sufiiciently far along their path oftravel to be slit by one of the pairs of cutting surfaces and the otherpair of cutting surfaces is provided with a disabling means to disablethe cutting function of the second pair by retracting them. The schemeprovides longer slit wedges for phase insulation purposes and shorterunslit wedges for bore slot wedges as the last step in fabricating thestator. One or both of the cutting surfaces may be provided with anadjustment means 69 which will allow the machine to be adjusted to slitinsulating material throughout a range of desired length depending uponthe configuration of the particular stator being assembled.

Numerous other modifications will suggest themselves to those ofordinary skill in the art and accordingly the scope of the presentinvention is to be measured only by that of the appended claims.

Iclaim:

1. In an automatic coil placing machine, an improved wedge makercomprising:

means for feeding wedge material in increments of a first length; meansfor severing the wedge material into wedge blank s of said first length;means or contemporaneously forming and slitting the wedge blanks; andmeans for inserting the thus formed and slit wedges into a stator.

2. The improvement of claim 1 further comprising means for modifying thefeed means whereby wedge material may be fed in increments of a secondlength.

3. The improvement of claim 2 further comprising means for at leastpartially disabling said forming and slitting means whereby material fedin increments of said second length may be formed without slitting.

4. The improvement of claim 1 wherein said forming and slitting meanscomprises:

a power operated punch, a forming die, and a plurality of cuttingsurfaces;

said punch forcing wedge blanks through said forming die and past saidcutting surfaces in a single stroke.

5. The improvement of claim 4 wherein said plurality is four and furthercomprising means for selectively retracting two of said four cuttingsurfaces.

6. The improvement of claim 5 further means for selectively modifyingthe feed means whereby wedge material may be fed in increments of asecond length and wherein said means for retracting is activated forwedges of the shorter of the two said lengths whereby said shorterwedges are formed without slitting.

7. The method of providing a plurality of wedges of each of at least twolengths of insulating material for the slots of a stator comprising:

feeding the insulating material from a roll of stock material;selectively cutting the thus fed material to provide wedge blanks of atleast two different lengths;

selectively contemporaneously forming a longer wedge into a U-shape andlaterally slitting that wedge, and selectively forming a shorter wedgeinto a U-shape without laterally slitting that wedge whereby both slitand unslit wedges may be produced.

8. A machine for providing two pairs of slits in a strip of insulatingmaterial, the two slits of each of said pairs extending inwardly fromopposite edges of the strip of insulating material toward each othercomprising:

a power operated punch, a forming die, and a plurality of fixed cuttingsurfaces;

said punch forcing said insulating material through said forming die andpast said cutting surfaces in a single stroke.

9. The machine of claim 8 further comprising a pair of retractablecutting surfaces, said plurality of fixed cutting surfaces positioned toprovide one of said pairs of slits and said pair of retractable cuttingsurfaces positioned to provide the other of said pairs of slits.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 sDated October 3, 1972 I t Robert G. Walker and Donald E. Hill It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

lines 27 and "U.S .Pat.No. second occurrence,

should be deleted.-

Col. 3, line 25, "the" omitted between "Thus" and "cuffed" Col. 6, line28 (Claim 6) "comprising" omitted between "further" and "means" Signedand sealed this 20th day of February 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. In an automatic coil placing machine, an improved wedge makercomprising: means for feeding wedge material in increments of a firstlength; means for severing the wedge material into wedge blanks of saidfirst length; means for contemporaneously forming and slitting the wedgeblanks; and means for inserting the thus formed and slit wedges into astator.
 2. The improvement of claim 1 further comprising means formodifying the feed means whereby wedge material may be fed in incrementsof a second length.
 3. The improvement of claim 2 further comprisingmeans for at least partially disabling said forming and slitting meanswhereby material fed in increments of said second length may be formedwithout slitting.
 4. The improvement of claim 1 wherein said forming andslitting means comprises: a power operated punch, a forming die, and aplurality of cutting surfaces; said punch forcing wedge blanks throughsaid forming die and past said cutting surfaces in a single stroke. 5.The improvement of claim 4 wherein said plurality is four and furthercomprising means for selectively retracting two of said four cuttingsurfaces.
 6. The improvement of claim 5 further means for selectivelymodifying the feed means whereby wedge material may be fed in incrementsof a second length and wherein said means for retracting is activatedfor wedges of the shorter of the two said lengths whereby said shorterwedges are formed without slitting.
 7. The method of providing aplurality of wedges of each of at least two lengths of insulatingmaterial for the slots of a stator comprising: feeding the insulatingmaterial from a roll of stock material; selectively cutting the thus fedmaterial to provide wedge blanks of at least two different lengths;selectively contemporaneously forming a longer wedge into a U-shape andlaterally slitting that wedge, and selectively forming a shorter wedgeinto a U-shape without laterally slitting that wedge whereby both slitand unslit wedges may be produced.
 8. A machine for providing two pairsof slits in a strip of insulating material, the two slits of each ofsaid pairs extending inwardly from opposite edges of the strip ofinsulating material toward each other comprising: a power operatedpunch, a forming die, and a plurality of fixed cutting surfaces; saidpunch forcing said insulating material through said forming die and pastsaid cutting surfaces in a single stroke.
 9. The machine of claim 8further comprising a pair of retractable cUtting surfaces, saidplurality of fixed cutting surfaces positioned to provide one of saidpairs of slits and said pair of retractable cutting surfaces positionedto provide the other of said pairs of slits.